THK SEKTL'LAKlli.i:. 127 



uniformly much higher. Moth Murray :inl Trask speak of tin- hydrothcc;e be'ino- supported 

 liy a sort <>t' triangular butlre-s (Murray), or a sliylilly ele\ated rounded rim (Trask). 1 Murray 

 adds that the gonangia arc. oblong-oval. 



SELAGINOPSIS Allman (modified). 



Trophosome. Ilvdrothec;e arranged in inure than tw<> longitudinal -eric-, at Ica.-t on di-ta) 

 parts of branches, or in two or more scries each of which lias (he distal ends of the h vdrother;e 

 turned alternately to the riylit and left. ( )perculuin of a single alicauline (lap. Intel-nodes lmi<j 

 or aliscnt. 



(iniiiiKiHii, . (ionano'ia Usually ol>o\ ate, without internal marsupium or external ornamen- 

 tation. 9 



Tliis dctinition of the o-enns is more comprehensive than I he original by Allman.' This 

 writer proposed two new genera at the same time, Selaginopsis to include forms with several 

 rows of liydrotliec;e set on simple branches, and /' ficliiiliniii to include form- with several row- 

 of hvdrotheca' set on liifurcatiny ramuli. In ls?s Merescbkowsky, without having seen Allman 's 

 paper, proposed the e.-enus Polyseriasko include sertularians with hydrothecse arranged in several 

 rows (iii the liranchcs, but which arc hiserial on the stem. Later. but duriny the same year, he 

 wrote another paper' in which he acknowledged the priority of Allman'- ovneric name S,l,ni'ui- 

 <yi.v/'.v, lint proposes to include in that ycnus the forms that Allman pul in /' r'icl<nHii m . \ little 

 later. Is'.in, Marktanner-Turneretscher 5 reeooni/cd the o-enus substantially as dctincd by 

 Mereschkowsky. In iv.i:; Levinsen' in pursuance of his policy of rclyiny entirely on the char- 

 acters of the hydrothccal margin and operculum, included the species here considered as belong 

 inn- to X l,iiiiniifixix in the jjfeniis 77; uitir'ni. on account of the single-flapped abcaiiline o[)crcnlum. 



The yvmis Selaginopsis as abo\ c defined seems to me to be a perfectly tenable <_;Toup. indeed 



one of the best genera in the family Sertularidse. Lts affinities are evidently with Tlm/in-iii. from 



which, however, it is shar|)ly differentiated by the ai'rangemenl of the hydrotheca'. 



There are no points of iritersradation between this grenus and others that need offer anv 



IT O O 



difficulties in the allotment of sjiccics to this o'cniis as here defined. In most species the hydro 

 thecaj of the stem arc arranged in two opposite series, as in Tlminriii. and in some, cases this is 

 true of the proximal parts of branches. But in these same species the hydrotheca' on all but the 

 proximal parts of the branches are poly serial, furnishing a perfectly evident character for 

 generic identification. 



KEY TO AMERICAN M'KIIKS OK TMK (.i:\IS -KI.Ai . I M )l'.-l>. 



The tydrothecee in :i Driven m\\ not turning alternately to rii/lit ami li-ft. 

 Distal ends of livlrollirc.-r distinctly exscrti'il. 



Miiririn ith two distinrt Iceih uitniliHi.*. 



Margin without tcctli jiiimxl' r. 



Distal ends of \\\ drotliiv;i- not greatly exsiTti-d. 



Hydrotlici'ii' in tliive rows I rim ri'i/i*. 



llydrotlici-r in four rows. 



Stem and liranrhes u'cniciilatr, branching regularly Compound />////i inn is. 



Stem and liranrhes not L'enirnlate, branrlirs not regularly compound: 



Two pairs of lira] n -lies to cadi intcrnodc of stem cedrina. 



Sti'in very lieavy and w oody. Nodes ilrcp, ai inpanii'd 1 iy ami illations /liinuihi. 



Co-uosarcal canals in liranc-hes very regular and four in number, (ionanjria with niiiiiei-niis \ei-y 

 long cnrveil processes nrnnhi. 



'Annals an 1 Ma^a/.ine, :;d ser., V, pi. \n, tii.'. 1", represents cadi internodc of the branch as bearing three 

 hydrotlicc;c, in one case tw o, which nmliniis Trask's description and ti'.nire. 



-The known exceptions ainon;_' American species arc N. uriniln and N. i-nlrinn. 



3 Journal of I he I, inn.' can Society, /oology. XII. Is7 I. p. L'7L'. 



1 Xew llydroida from dchotsk. Kamtschatka. and other ]iarts of the North Pacific ( lei -an. Annal> and Ma'ja/.ine 

 of Natural History. :>th ser., II, ls?s, p. I:; I. 



5 Ilydroiden des k. k. natiirhistorischcn 1 lolmii.-enms. Is! HI. p. L'lL'. 



6 Meduser, Ctenophorcr o._' llydroidcr fra < imnlands \"<'stkyst, p. 193. 



5125 PT 204- 



